1. Field of the Invention
The present disclosure relates to a display device, and more particularly, to a stereoscopic image display device to achieve enhanced brightness during 3D image display using a switchable barrier and brightness enhancement polarizing films.
2. Discussion of the Related Art
At present, services for rapid dissemination of information, to be constructed based on high-speed information communication networks, have developed from a simple “listening and speaking” service, such as current telephones, to a “watching and listening” multimedia type service based on digital terminals used for high-speed processing of characters, voices and images, and are expected to be ultimately developed into hyperspace 3-dimensional stereoscopic information communication services enabling virtual reality and stereoscopic viewing free from the restrains of time and space.
In general, stereoscopic images representing 3-dimensions are realized based on the principle of stereo-vision via the viewer's eyes. However, since the viewer's eyes are spaced apart from each other by about 65 mm, i.e. have a binocular parallax, the left and right eyes perceive slightly different images due to a positional difference between the two eyes. Such an image difference due to the positional difference between the two eyes is called binocular disparity. A 3-dimensional stereoscopic image display device is designed based on binocular disparity, allowing the left eye to view only an image for the left eye and the right eye to view only an image for the right eye.
Specifically, the left and right eyes view different 2-dimensional images, respectively. If the two different images are transmitted to the brain through the retina, the brain accurately combines the images, reproducing depth perception and realism of an original 3-dimensional (3D) image. This ability is conventionally referred to as stereography (stereoscopy), and a display device to which stereoscopy is applied is referred to as a stereoscopic display device.
Stereoscopic display devices may be classified based on constituent elements to realize a 3-dimensional (3D) image. In one example, stereoscopic display devices are classified into a glasses-type stereoscopic display device in which shutter glasses allow a target eye to catch an image and prevent a non-target eye from catching the image, allowing both the eyes to selectively catch different images, and a non-glasses type stereoscopic display device using a lens or barrier.
Examples of non-glasses type stereoscopic devices include an electrically-driven liquid crystal lens type stereoscopic display device, which achieves lens effects by creating an optical path difference based on an electrode pattern difference between regions when voltage is applied, and a barrier type stereoscopic display device which separately transmits a left-eye image and a right-eye image via slits between barriers.
However, a conventional barrier type stereoscopic display device has deterioration in opening rate and brightness due to a barrier pattern.
This problem of the conventional barrier type stereoscopic display device will now be described in detail.
If a region in which the barrier pattern is located includes a reflective metal pattern, the reflective metal pattern may intercept light directed from therebelow, causing deterioration in opening rate and brightness.
A switchable barrier may be used to prevent deterioration in opening rate and brightness. The switchable barrier functions to completely transmit light directed from therebelow during 2D image display, but is divided into black and white regions such that only the white region transmits light during 3D image display. Thus, when displaying a 3D image using a switchable barrier type stereoscopic display device, the black region functions as a barrier pattern, causing considerable brightness deterioration.